Grease gun filter attachment



April 1950 J. H. HARNLEY- 2,504,683

GREASE GUN FILTER ATTACHMENT Filed May 1, 1947 Fig. 1.

JNVENTOR. Jblzzz H. Harnle z Patented Apr. 18, 1950 uumzo sures PATENT OFFICE GREASE GUN FILTER ATTACHIVIENT John H. Har'nley, Gray County, Tex. Application May 1, 1947, Serial No. 745,299

1 Claim.

This invention relates to a filter attachment for grease guns and the like and more particularly to hand operated grease guns of the type commonly employed for the purpose of forcing grease into the bearings of farm machinery.

Owing to the conditions under which the lubricants employed about a farm are stored they frequently become contaminated with straw, chafi and similar foreign matter which is drawn into the gun barrel during the filling of the latter. The result is that when the gun is employed in a greasing operation it is frequently rendered inoperative owing to the lodging of a fragment of foreign matter beneath the discharge valve so as to prevent the latter from performing the proper function. When such a mishap takes place it becomes necessary to return the gun to a place where the valve can be removed and repaired or a new valve substituted. When the mishap occurs far afield it is evident that much valuable time is lost not only because of the transportation of the gun to and from a service point but because the machinery must be kept out of service until it can be supplied with the lubricant.

The primary object of this invention is to conserve the time and energy absorbed in servicing the gun and to keep the machinery properly functioning.

Another object is to prevent the introduction of dirt, grit, chaff and like foreign matter into the bearings of farm machinery during the lubrication thereof.

Another object is to enable filter screens of different mesh to be employed in the same grease gun and also to facilitate the cleaning of a clogged filter screen.

The above and other objects may be attained by employing this invention which embodies among its features a bushing adapted detachably to be coupled to the discharge end of the barrel of a grease gun, an internal annular shoulder in the bushing, means to couple the discharge pump of the grease gun to the bushing and a filter screen abutting the shoulder in such a manner that grease being expelled from the gun barrel will have to flow through the filter screen before it can enter the pump.

Other features include clamping the filter screen between the pump and the shoulder so that it easily may be removed for cleansing or interchange with another filter screen of a different mesh.

In the drawings-- Figure 1 is a fragmentary side view of a grease gun equipped with this improved filter attachment, certain portions being shown in section,

Figure 2 is a side view of the bushing with parts shown in section more clearly to show certain detail of construction,

Figure 3 is a perspective view of a filter screen, and

Figure 4 is a view similar to Figure 2 showing a modified form of the invention.

Referring to the drawings in detail, a conventional grease gun designated generally l0 comprises a barrel 1 l of generally tubular form closed at one end by a head l2 equipped with an axial opening surrounded by a packing gland [3 through which a piston rod l4 enters the barrel. This piston rod carries at its outer end a handle l5 and its opposite or inner end is threaded to receive clamping nuts l6 and washers I1 between which a conventional cup-shaped leather washer I8 is clamped in a conventional manner to form a piston which seals against the wall of the barrel to prevent the escape of grease there-around during the expulsion of the grease from the barrel.

The end of the barrel H opposite the head I2 is externally screw-threaded as at 19 for entrance into the internally screw-threaded cap 20 closing the end of the grease gun opposite the head I2. This cap 20 is equipped with a conventional grease passage 2! which opens into the bore 22 of a conventional grease pump 23 carried by the cap 20 and mounted for reciprocal movement in the base 22 in a conventional piston 24. Opening radially into the bore 22 near its inner end is an internally screw-threaded bore 25 in which a valved discharge nipple 26 is threaded. This nipple 26 is equipped with an internal valve seat 21 upon which a ball valve 28 seats under the influence of a spring 29. The structure so far recited is all of conventional form.

My improved filter attachment designated generally 30 comprises a tubular body or bushing 3| formed at one end with an externally screwthreaded nipple 32 and at its opposite end with an internally screw-threaded socket 33. Formed intermediate the ends of the body 3| and at the inner end of the socket 33 is a shoulder 34 the purpose of which will more fully hereinafter appear. The threads in the threaded socket 33 of the body or bushing 3| are cut to match the threads I9 of the barrel l I and the threads on the threaded nipple 32 are cut to match the threads in the cap 20. It will thus be seen that the attachment readily will fit a conventional grease 3 gun. Obviously when the barrel is internally threaded and the cap is externally threaded, the attachment need only be reversed when coupling it to the gun.

Seated against the shoulder 34 and extending transversely of the axis of the body 3| is a filter screen designated generally 35 which in its preferred form comprises a disk 36 of wire mesh having the desired degree of porosity about the peripheral edge oiwliich is crimped a circular frame 31 having an external diameter easily to fit into the threaded socket 33. The filter screen 35 is clamped in the body 3! between the threaded end of the barrel I l and the shoulder 34 and thus easily may be removed for cleansing or replacement. It will be understood that the size of the mesh of the screen fabric may vary to suit the type of service and that several difierent filter screens may be interchangeably employed in'a single attachment. I

In order to further exclud 'hafi, straw and like ror'eign jinatter from the pump 23 and valve '28 I find it advantageous to employ a filter V screnidesignated generally v 38 whichis clamped between the end of the nipple 32 and a suitable Spacing washer 39 fitted in the 08 520. r

In the modified form of the invention illustrated in Figure 4, the attachment designated generally 46 like the attachment 3!] comprises a V tubular body 1] having atone end an externally screw-threaded nipple 42 and at its opposite end antnte'rnallyscrew-threaded socket 33 which like these previously described are adapted to be coupled to the'g'rease gun barrel and the grease g'u'neap. Formed in the tubular body an intermediate its ends is a shoulder '44 against which a fllter'disk 15 1s seated. Unlike the filter scree 35, 'the filter disk 45 has its peripheral edge soldered as at 46 to the wall of the body 4! so that the filter disk is permanently fixed in the body. 7 v

'In use it willbe understood that the'spout or cap'ZIJ i's uncoupled from the grease gun barrel 1H and the gun filled with lubricating'grea's'e-in the conventional manner. Before replacing the cap on the barrel, however, a filter screen of the fiesiledime sh is inserted in the body '35 against theshould'er 34 and the threaded-end or the barrel H is threaded into the socket "33 to clamp the frame 31 firmly against the shoulder 34. The threaded nipple 32 isthen threaded into the cap 20 and the 'gun is read-y'for use. Obviously if so desired a-seconu filter screen 33 may be clamped between the end of the nipple 32 and a spacing ring '39 seated in the cap 20 soas to be doubly sure that chaff and like 'foreign matter is excluded from the pump-S23. By the simple expedient of unscrewing the cap 20 from the nipple 32 the filter screen '38 :therein. maybe removed and "another .substituted therefor or by. the unscrewing of the barrel I I from the socket 33, 'the'screen35 maybe removed. Hence it'ispossible to clean the filter screens without taking the gun out of service more than the few moments required to exchange screens. The modified form of the invention illustrated in Figure 4 is coupled to the grease gun in identically the same manner as the device previously described, but owing to the fact that the screen fabric disk 36 is soldered in the body 32, the rapid interchange of filter disks is sacrificed for the advantage of permanence of assembly.

In certan instances it may be desired to solder or otherwise fix a filter screen 47 in the passage 2i. In any event a filter screen or a plurality of filter screens ifiterposd between the discharge end of the barrel H and the pump 23 and valve 28 will serve to exclude foreign matter from the valve so that it cannot be held away from its seat 2'! and its proper function interfered with. Thus great savings in time may be effected.

While in the foregoing there has been shown and described the preferred embodiment of this invention, it is to be understood that minor changes in the details er construction, combina- =tion and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as claimed.

What is claimed is:

In a grease gun "of the type comprising a barrel having an open end, screw threads adjacent the open'end of said barrel, a piston within the barrel for forcing grease through the open end thereof, a cap threaded on the open :end of the barrel having passages through which grease leaving the open end of the barrel is discharged and a gasket in the cap for engaging the end of the barrel; a filter attachment for said grease gun comprising a substantially cylindrical body having a .bore extending therethrough which corresponds in diameter substantially to the internal diameter of the barrel, internal screw threads on one end otthe body for cooperation with the threads on the barrel in detachably securing the bodyto the barreL-external screw threads on the .opposite end of the body for detachably securing the cap thereto, an internal annular shoulder within the body intermediate the ends thereof, a disk shaped filter screen within the body clamped between the'threaded end of the barrel and the shoulder and "a second disk shaped filter within the cap clamped between the end of the body remote from the'barr'eliand the gasket in the JOHN H. HA-RNLEY.

REFERENCES CIT-ED free following rer'ere'neesare of record in the me or this patent:

UNITED STATES PATENTS 

